Methods of this type are known from the aircraft manufacturing industry in particular. In this field, a hybrid connection is characterised by the adhesive bonding and mechanical spot joining of two joining parts, the adhesive layer being arranged in the region of the mechanical joining points. With the conventional hybrid connection methods, it is difficult to accurately obtain a uniform adhesive layer thickness which should remain unchanged even when being loaded by the mechanical joint connections themselves.
With a known hybrid joining method, in which adhesive bonding and riveting are carried out simultaneously, glass beads with a predetermined diameter are added for example to the adhesive used in order to adjust the thickness of an adhesive layer between the two parts to be joined, and this ensures that the thickness does not fall below a minimum thickness, corresponding to the diameter, of the adhesive layer. Owing to the rivet connection and the related high force of pressure in the region of the rivets involved in this procedure, the glass beads used are pressed into the respective surface coating of the joining parts, which results in both the surface coating and, to some extent, the glass beads being destroyed and so the level of precision achievable with this method cannot be ensured.
Other methods which involve both adhesive and rivet connections initially adhesively bond the joining parts to one another in order to subsequently produce the rivet connection after the adhesive has cured. In order to obtain a defined adhesive layer thickness, the joining parts are clamped in devices after the adhesive layer has been applied and remain fixed therein until curing has occurred. A drawback of this type of method is the long process time, since clamping the joining parts is time-consuming and it is further necessary to wait until the adhesive has cured.
In a further known method involving both adhesive and rivet connections, the layer thickness of an adhesive between two joining parts is adjusted by the viscosity of the adhesive. In this case, after the adhesive layer has been applied, rivet holes are produced and the joining parts are riveted to one another before the adhesive layer cures. Owing to the force of pressure produced by the riveting process, adhesive is squeezed out of the gap between the joining parts, adhesive of a thickness which can be predetermined from the viscosity of the adhesive remaining in said gap. The layer thickness achieved by this type of method is generally too small to achieve a sufficient level of mechanical adhesion and the adhesive is further not completely uniformly distributed. Accumulations of adhesive or vacuities (“pockets”) are formed locally.